Audible signal for railway braking apparatus



v 1,641,768 p 1927- L. v. LEWIS AUDIBLE SIGNAL FOR RAILWAY BRAKINGAPPARATUS Filed July 17, 1926 INVENTOR I Patented Sept. 6, i927.

sis rrsnr LLOYD v.1.nwrs, on Enenwoon BOROUGH, PENNSYLVANIA, AssreNon TOTHE UNION SWITCH & SIGNAL COMPANY, OF SVJIS OF fENNSYLVANIA.

SVALE, FENNSYLVANIA, A CORPORATION AUDIIBLE SIGNAL FGR RAILWAY BRAKINGAE'PARATUS.

Application filed July 17,

My invention relates to railway automatic train control apparatus, andparticularly to apparatus of the type wherein time. interval elapsesafter a stop. indication is received before a brake application isincurred. One feature of my invention is the provision of means forgiving an audible signal during this time interval, so that the engineman may be on the alert to prevent anautomatic brake applicationreducing the speed or acknowledging the restrictive indi cation.

I will describe one form of apparatus embodying my invention, and willthen point out the novel features thereof in claims.

The accompanying drawing is view showing one form of apparatus embodyingmy invention.

Referring to the drawing, the apparatus here illustrated, all of whichiscarried on a railway train, comprises a reservoir A, which is normallycharged with fluid pres sure toprevent an automatic brake application,but the pressure in which is reduced to brake applying value underunsafe trafflc conditions at a rate dependent upon the speed of thetrain. Usually this reservoir will be so controlled that as the speed ofthe train decreases, the rate of pressure reduction decreases; Forexample, if the restrictive signal indication is received when the speedis miles per hour, the brake application maybe incurred 5 secondsthereafter, while if the restrictive signal indication is received whilethe speed of the train is 20 miles per hour the brakes may apply secondsthereafter, the delay period being of proportionate intermediate valuesat speeds intermediate the limits specified. One form of apparatus forcont-rolling this reservoir in the manner specified and for causing abrake application when the pressure in the reservoir is reduced to agiven value, is shown in United States Letters Patent Reissue No.16,083, granted to Frank H. Nicholson'on May 26, 1925, wherein two suchreservoirs are disclosed, one of which is designated T and the other ofwhich is designated T The reference character B designates a whistle,and the reference character 6- designates a whistle-operating reservoir.The supply of fluid pressure from the reservoir A to the reservoir C andsubsequently from 1926. Serial No. 123,085.

the reservoir C to the whistle Bis controlled by a. valve D.

The valve D comprises a body member 3 having a chamber 12 provided withtwo oppositely disposed seats 6 and 8. The relatively small seat 6communicates withthe whistle B through a port 5 and a restricted orifice7, while therelativelylarge seat 8 communicates with the brakecontrolling reservoir A through a port 9 and pipes 2 and 1. The chamber12 communicates with the whistle operating reservoir C by a pipe 4.Located-in the chamber 12 is a diaphra m designated as a wholeby thereference character 10, and comprising a central position normallyengaging the valve seat 6, as well as a thin flexible flange normallyresting on the valveseat 8. The entire diaphragm is preferably made of'rubber. This diaphragm is normally in the condition shown in thedrawing, wherein both the ports 9 and 5 are closed, but it may bulgedownwardly as a whole to open theport' 5 to chamber 12 and so toreservoir C, and

the flange 10 may also. bend upwardly to open communication between ththe pipe 4.

I- will first assume that the brake controlling reservoir A is atatmospheric pressure and that the pressure in this reservoir is thenincreased. As the pressure in reservoir A increases, the flange' IO ofthe diaphragm 10 will bend upw-ardly'to admit e port 9 and pressure toreservoir 0, so that when the pressure in reservoir A reaches itsmaximum value thereservoir G will containfluid pres sure atsubstantially the same value. During this time the portion 10? of thediaphragm 10 has remained in contact with the valve seat 6 so that thewhistle B has been silent. I will next assume that a restrictiveindication is received, so that the pressure in the reservoir Adecreases. The pressure above the valve member 10 isnowgreater than thatbelow this member, so that the diaphragm 10 bulges downwardly away fromthe valve seat 6, thereby admitting fluid pressure from the reservoir Cto the whistle B and sounding this Whistle to inform the engineman thata restrictive indication has been received. The whistle will blow aslong as the pressure in reservoir A continues to reduce, andduring thistime the engineman may either reduce the speed below the brakes but theto brake applying value under unsafe trafvalue required bythe particularindication which has been received, or he may take other stepsto preventan automatic application of the brakes. One form of apparatus wherebythe engineman may prevent a brake application during the interval thatthe whistle is blowing is shown and described in the aforesaid NicholsonReissue Patent No.

Preferably a gauge E is connected with the reservoir A by pipes 11 and 1to show the engineman the actual pressure in this reservoir and toinform him as to approximately how long he may wait'after a restrictiveindication is received before taking steps to prevent an automaticapplication of the brakes.

Although I have herein shown and described only one form of apparatusemb0dyo ing my invention, it is understood that various changes andmodifications may be made therein within the scope of the appended 7claims Without departing from the spirit and 1 fic conditions at a ratedependent upon the speed of the train,,a whistle, a whistle operatingreservoir, a valve having a chamber communicating with said whistle andwith saidtwo reservoirs, and a flexible diaphragm in said chamber forconnecting said-whistle operating reservoir with said brake controllingreservoir while the pressurein the lat-V ter is increasing and forconnecting the whistle operatingreservoir with the whistle while thepressure inthe brake controlling reservoir is decreasing. I

2. Train carried governing comprising a brake controlling reservoirwhich is, normally charged with fluid pressure to prevent automaticapplication of the apparatus brakes but the pressure in which is reducedto brake applying value under unsafe trafiic conditions at a ratedependent upon the speed of the train, a whistle, a whistle operatingreservoir,'a valve having a chamber communicating with said whistleoperating reservoir and provided with two oppositely disposed seatscommunicating respectively with said whistle and said brake controllingreservoir, and a flexible valve member normally engaging both of saidseats but capa bl-e of bending to permit charging the whistle operatingreservoir while the pressure in the brake controlling reservoir isincreasing and cap able'of bulging away from the whistle seat to ventthe whistle operating reservoir to the whistle while the pressure in thebrake controlling reservoir is decreasing.

3. Train carried governing apparatus comprising a brake controllingreservoir which is normally charged'with fluid pressure to preventautomatic application of the brakes but the pressure in which is reducedto brake applying-value underunsafe traffic conditions at a ratedependent upon the speed of the train, a whistle, whistle operatingreservoir, a valve having a chamber communicating with said whistleoperating reservoir and provided with two oppositely disposed. seatscommunicating respectively with said whistle and said brake'controllingreservoir, the whistle seat being relatively, small, and the other seatbeing relatively large, and a diaphragm having a central portionnormally engaging said whistle seat and a flexible flange normallyengaging the other seat,.said flange being capable of bending in wardlto ermit char 'in the whistle 0 erating reservoir while the pressure inthe brake controlling reservoir is increasing, and said flange beingalso capable of permitting the central portion to bulge away fromtheseat to vent the whistle operating reservoir to the whistle while thepressure in the brake controlling reservoir is decreasin In testimonywhereof I'allix my signature.

LLOYD v. L'EWIS.

